1. Field of the Invention
This invention relates to a method for observing high-altitude neutral air and a device for observing high-altitude neutral air which are usable in space operational business enterprise and space weather forecast business enterprise.
2. Description of the Related Art
Data concerning high-altitude neutral air is very important because the orbital altitude of a space satellite may decay due to the atmosphere drag in the high-altitude neutral air and the reentry of the space satellite into the atmosphere can be predicted from the high-altitude neutral air data.
In a conventional observation for the high-altitude neutral air, an observing instrument is mounted on a space satellite, which is disposed in the high-altitude neutral air. As a result, since the observing instrument is positioned in a given area of the high-altitude neutral air, the observation for the high-altitude neutral air is carried out at every area where the observing instrument is positioned.
Since the observing area is contaminated by positioning the space satellite, with the conventional technique, the high-altitude neutral air can not be observed precisely. Moreover, with the conventional technique, only the data concerning a given area of the high-altitude neutral air by positioning the observing instrument in the given area can be obtained, so the total data concerning the high-altitude neutral air can not be obtained simultaneously.
The data concerning the high-altitude neutral air can be obtained from the Jacchia model (Standard Jacchia Reference Atmosphere 1977) which is a simulated and modeled distribution of high-altitude neutral air based on the changes in altitude of many previously launched space satellites. Since the predictive accuracy of the Jacchia model is poor, it can not be employed in a technical field requiring prompt response and accuracy such as the prediction of the reentry of a space satellite.